Surface integrity design of plasma sprayed coating for resisting contact fatigue

• The surface integrity influences RCF behavior of coating.
• The competitive failure process is the main feature of RCF process.
• Changing the failure mode is an effective approach to extend RCF lifetime.
• The optimal design of the surface integrity of coating is important.

The influence of the surface integrity on rolling contact fatigue (RCF) behaviors of plasma sprayed coatings was investigated. The four parameters of the surface integrity were introduced to discuss, such as bond strength, surface hardness, coating thickness and surface roughness. The result showed that the surface integrity can obviously influence the competitive failure process of the coating under rolling contact. The appropriate surface roughness is positive for the formation of excellent lubricant status. Consequently, the failure model changes from wear failure with the shorter lifetime to fatigue failure with the longer lifetime. The optimal designs of bond strength, surface hardness and coating thickness are positive to increase the fatigue-resistance of the coating system and extend the service lifetime.